You just explained the current issue with dungeons and just about everything currently in the game. Things lack a significant replay value and become a chore. This is the exact reason they are due for a change. Besides, if we went with those thoughts why add anything at all. A chore today is a chore tomorrow and so on, if dungeons were a chore then we would be ok with running them for the next 2 years without any addition of new dungeons. They're just chores after all.

The current dungeons are equal to a day job. You know exactly what to expect and you literally go in to just 'put in your time'. A design request to add some form of replay value would alleviate some of chore/job of it. Really it just comes down to letting the dungeon leads go wild once in awhile, or telling them to put some imagination and fantasy into the game.